Who flexes the most muscle on Wall Street? Earlier this week, CNNMoney showed you that it's not hedge funds and bank CEOS, but their massive sovereign wealth funds of countries like Japan, China and Norway.

But what about here in the United States? It's not corporate bosses or the even the 1%. Rather, its teachers, police officers, firefighters, or anyone else in a large public pension. In an era when governments are tightening their belts and a surge in Baby Boomer retirements is fast approaching, these pension funds are under a great deal pressure to generate big returns.